The present invention relates to burner apparatus, and particularly to industrial burners for mixing air and fuel to produce a combustible air-and-fuel mixture. More particularly, the present invention relates to a burner apparatus having an air-and-fuel mixing nozzle.
Burners are frequently used in industrial environments to provide heat to various processes. For example, burners are used to provide heat to boilers, furnaces, kilns, rotary dryers, fume incinerators, and pollutant-burning afterburners. Many burners are configured to convert air and fuel into a combustible air-and-fuel mixture which is then ignited to produce a flame for providing heat to a process. Many burners employ complex mixing schemes involving multiple parts which are expensive to manufacture, produce high emissions, and/or have low turn-down ratios.
According to the present invention, a burner apparatus includes a case coupled to an air supply and a nozzle positioned to lie in the case and coupled to a fuel supply. The nozzle defines at least one air-flow cavity inside the case. The nozzle is formed to include a fuel-distribution chamber and at least one fuel-discharge port to communicate fuel from the fuel-distribution chamber into air passing from the air supply through each air-flow cavity. The fuel mixes with the air in each air-flow cavity to produce a combustible air-and-fuel mixture therein which can be ignited to produce a flame in the case.
In preferred embodiments, the nozzle includes a body formed to include the fuel-distribution chamber and an annular side wall and eight vanes appended to the annular side wall and arranged to extend radially in directions away from the fuel-distribution chamber. The vanes are circumferentially spaced apart from one another about the annular side wall of the nozzle body and each pair of adjacent vanes is arranged to define an air-flow cavity therebetween.
Three fuel-discharge ports are associated with each air-flow cavity and formed in the annular side wall of the nozzle body to discharge fuel from the fuel-distribution chamber into each air-flow cavity. Air passing through each air-flow cavity mixes with fuel discharged through the fuel-discharge ports to create a combustible air-and-fuel mixture that can be ignited to produce a flame.
A bluff-body flame holder is provided in all but one of the air-flow cavities to give stability to the flame produced by the, burner. An ignitor is mounted in the one air-flow cavity that does not contain a bluff-body flame holder.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments of the invention exemplifying the best mode of carrying out the invention as presently perceived.